A great deal of people have reported the power-down "thump" or "pop" problem on the Mk1's. Experiences vary, so I'm trying to collect some concrete evidence.

If you are a victom of this phenomenum, can you anaswer the following:

1) Under what situations exactly do you encounter this? (eg., empeg powered on, ignition off causes thump, etc.)

2) Is your power amp a MOSFET or high-impedance FET input type?

3) What model/make of amplifier are you using?

4) Is there a web-site URL for your amp? (alternatively, PDF formatted data sheet or other spec sheet?)

I'm looking forward to your replies!

1) Under what situations
While starting the car's engine. Can't remeber exactly if it mattered if empeg was on or not. Bacause of the pops I developed the habit to insert the empoeg only once the engine was running, until last week . . . . I forgot to remove empeg when the engine halted. Started the egine, and since then the amp is dead. Funny enough, there was no last pop.

Had had a dead amp before. Previously it came back to life after some 5 minutes.

2) (MOS)FET
Mine is (was ) a MOSFET type amp

3) Model / make
Make: Rockford Fosgate
Model: Punch 240.4

4) URL
http:// http:www.rockfordfosgate.com
there are no data sheets for this model on their site, I believe. There is a PDF manual: fisrt item (manual for 160.4 and 240.4 models) here

Henno

I find it hard to believe that the pop on power off would have killed an amp - this is the sign of a very bad amp design, at best.

One of our customers has come up with a simple, 2-relay solution to the pop-on-poweroff problem, which is quite neat. Firstly, put a relay in the amp remote line, controlled by the accessory line (so that when the power goes off, the amp gets turned off with the ignition).

Then, connect the empeg's red wire to a permanent 12v feed though another relay. Power this relay from the accessory line through a diode and 330uF capacitor (the value of the capacitor needed will vary according to the size of the coil in the relay):

            diode
accessory ---->|---.----------------- relay coil
                  +|
                   = capacitor
                   |                 
ground ------------.----------------- relay coil

...this gives a good 0.5 sec between amp-off and empeg off.

Hugo

Hi,

If anyone wants the full schematic and parts list for the circuit, drop me a line.

john@bjnet.demon.co.uk

Regards,


----------------------------------
John

I get the power-off pop just about every time I turn the car off (Empeg running). In my install, the Empeg is going line-level into my factory head unit, an Eclipse made by Fujitsu-Ten. I don't know if they offer tech data on their website or not. I haven't put in the resistor that the Empeg team recommended because it doesn't bother me that much, and no one else seems to notice. If the MkII still has this issue, I'll put in a resistor when I change out the sled.
Jason

_~= Dearing =~_
"WAY too happy about having #99."

Hi ! I have a sony amp, sorry not sure which model right now. But I used to have that
pop at shutdown, but then I started playing with the switches on the amp and one
of them you can select hpf or lpf, i put both front channels on hpf and the rear
channels on lpf and now I don't have any pops at all ever.


Reg_2845 Serial #00173

I find it hard to believe that the pop on power off would have killed an amp - this is the sign of a very bad amp design, at best.

Got the amp back from repairs today. It proved unharmed
More alarming is that the fault is not in the amp, but in empeg!
The line-outs to the amp for in-car use are dead; the connects for home-use, when fed into the car amp, work OK.

Any clue what could be wrong?
Is there anything in the empeg that could have killed sled-output without affecting home-use?
Is it repairable, or do I need to send it into Cambridge??

Henno



Henno
# 00120

It would take some bad luck to kill ALL of the in-car outputs - this isn't something we've seen before.

Forgive me for sounding patronising, but you HAVE checked that the volume is turned up have you? I think your system went wrong around the same time that we introduced independent home and in-car audio settings.

Assuming you tried that, and checked that there are no problems with your line connections from the sled to your amp, and that the remote line is powering the amp up correctly, I suggest you email support@empeg.com and we'll get your player fixed as quickly as we can.

Rob

Forgive me for sounding patronising, but you HAVE checked that the volume is turned up have you? I think your system went wrong around the same time that we introduced independent home and in-car audio settings.

Surely he's checked the volume. What he really needs to check is his fader.

If he only has his amps connected to one pair of outputs, his fader could be set full-front or full-back and he might not know it. You also might want to check the equalizer to make sure it's not messed up for some reason.

And, like you said, checking the amp remote turn-on lead is important, too.



Tony Fabris
Empeg #144

> Surely he's checked the volume.

People have been known to overlook this.

Rob

It can't be the volume control in this case since the 1V outputs work and the volume setting is stored based on the power source not which outputs you're using (or whether you're actually in the car - my unit thinks it is at home even when it is in the car 'cos it's being powered through the power jack - maybe it thinks I live in an earthquake zone.).

--
Mike Crowe
I may not be speaking on behalf of empeg above :-)

HAVE checked that the volume is turned up have you?
Yes, I did check. Started out checking this before doing anything else, making sure that it was not at an ugly high setting so it would blow the speakers

Also checked fader, balance, pause.
Tested REM-out; measured voltage; the whole works.
Tested speakers/leads; speakers produced a soft pop when leads were connected to small battery.
Tested if speakers were shorted..
Replaced the amp with another one (we did all of this in the car hifi fitting station): no improvement.

Then: voltage on amp proved to drop when the amp set in.
I had measured the voltage on the amp to drop to 0V within a second after it was activated before (one of the reasons for returning it). Now we found the same behaviour, using one of these light pens that glow up (red light) when power is detected between the probe and earth. Without load, the light was bright. As soon as the amp kicked in, the light would fade to a very output within a second. After some minutes (power disconnected from amp) voltage would recover / light glowing bright again. We traced this back to the fuse mounted near the car battery. Replaced the fuse. This cured the power drop, but still no output in the car.

When empeg proved to drive the speaker from the cinch connectors for home use (connected from the bench, outside the sled), a faulty amp or peaker wiring were eliminated from being the cause of the problems. The shop guys (very helpful / interested on Empeg) had me convinced that the fault had to be in Empeg.

Very late last night / early this morning, the guys started to rebuild everything that had been taken apart.

And then (I had left Emma in playing mode), it suddenly decided to drive the speakers! Problem gone. But I'm very puzzled and worried now:

- Is there anything in Empeg than can it make to loose (and pick-up again) all 4 channels at the same time? Is there any single point of failure the 4 channels share? Any protection circuit/fuse or fault condition that can cause it to loose car-out, not cinch-out?
- Could a software upgrade (9a or 9b) have muted all car output?
- Anyone know any kind of failure that could cause a fuse failure as described?
OR
- Do I have an intermittent amp problem?

Remember:
- Empeg was removed (for the bench test) and re-inserted before it came back
- Empeg/Amp had lost all output after pops before I sent the amp back. Sound usually came back within 5 minutes after a pop, except the last time (before I sent the amp back, believing it had died)
- I'm about to fit a larger disk and will only do so on a healthy Empeg.

Henno
# 00120

The only single point of failure I can think of would be the sled connector -
which, incidentaly, I think is starting to play up on my unit.

The docking connector isn't really a common link between ALL of the outputs, as the ground is only common to a stereo pair, not to all four outputs. It is possible that both ground sets (or all four signal sets) could snap off if over stressed, but the chances of them reconnecting themselves later are slim to say the least.

Internally, the audio is common to the car mount and the in-home jacks right up to the final differential pre-amp stage. A loose pre-amp board could cause the fault, but as I said before, I think it's unlikely.

I'd be inclined to wait a while and see if the fault recurrs.

Rob

ground is only common to a stereo pair, not to all four outputs ( . . )
the chances of them reconnecting themselves later are slim to say the least

especially since both of them decided to reconnect at the same time! Highly unlikely, unless ARM intelligence extends to the connector.

I'm intending to add a 18.1GB Toshiba next week. Could/should I check the pre-amp board? Should I postpone the upgrade (disk is on its way?

PS1: Should there be any output on the car-output pins of the docking connectors when empeg is in 'home' mode?
PS2: We wanted to measure output on these pins yesterday, but the schematic on the empeg's top, nor the 'user manual' gave any detail where to find, which outputs. Could I suggest that you include pin-out info on later model(s)?

I'll keep a close watch on how things go. Will let you know if I strange things happen again.


Henno
# 00120

We wanted to measure output on these pins yesterday, but the schematic on the empeg's top, nor the 'user manual' gave any detail where to find, which outputs. Could I suggest that you include pin-out info on later model(s)?

I reverse-engineered the pinouts on my unit before installing the sled, just in case such a situation came up. Unfortunately, I don't have my notes here with me right now.

Good news is that the developer site has the pinouts right here. Enjoy!

Oh, and I wouldn't worry about putting that 18gb drive in there. If the Empeg goes bad, the drive can still be removed and used elsewhere.



Tony Fabris
Empeg #144

> Oh, and I wouldn't worry about putting that 18gb drive in there.
> If the Empeg goes bad, the drive can still be removed and used elsewhere.

I would imagine that he's more worried about invalidating his warranty, and player subsequently going bad.

Rob

> Could/should I check the pre-amp board?

The board sits at the rear of the player - it has a connector that couples up with the docking connector, and a ribbon lead which taps off some signals from elsewhere on the main board. It should be obvious if it is properly seated or not, and if the connections are satisfactory.

> PS1: Should there be any output on the car-output pins of the docking
> connectors when empeg is in 'home' mode?

Yes. You can check the car outputs whilst connected to AC power - refer to Tony's post for the URL of the docking connector pin-out.

Rob

I would imagine that he's more worried about invalidating his warranty, and player subsequently going bad.

Rob, you're close, but I'm not really worried that it'll go bad from adding the disk, or from new faults developing.
I am worried about the problems that have recently shown, causing my system (fuse/amp/empeg combination!) to go dead a few times Until earlier this week, I blamed the amp. But now the amp is (said to be) healthy, the fault could be in the empeg and I donot want to loose your support on sorting this existing (??) problem, by merely seating another disk.

At the same time, you guys have been honest and open on all issues raised here (you probably qualify for a couple of 'Awards of the Year' for innovation and service, for example -- too bad you'll still have to wait a year), such that I'm confident that we can sort things out if the fault is in Emma after all. Also Big John's de-thump device will cut out the pops on power down, so it may well be that the problem never shows again. And i'll check the pre-amp board too.

Henno
# 00120

I added a tri-mode crossover and a sub woofer this weekend, and whilst it has improved the sound in car a great deal, I now also have the "thump" problem too! This is now occurring when I power on the unit, so I get *thump* when the ignition comes on, followed by *thump* when the empeg decides it should be in power-down mode. So my wonderful theory about MOSFET charge storing on the amp input is most likely a lot of b******s. Funnily enough, it does not occur on power down or ignition off, but I have a pretty tiny amp.

Looks like I will be wielding the soldering iron sometime soon.